The most important historical-archaeological monument of Potaissa, Turda Municipality today, is the Fortress of the 5th Macedonian Legion, built on the Fortress Hill plateau, in order to strengthen the North-West defense of the Roman Dacia. This is the largest long-term fortress from this Roman province.
The fortress had a rectangular shape, with sides of about 400-500 m, an area of over 20 ha and sheltered approx. 5000 military. The defense walls had a thickness of about 2 m, being made of mortar and stone, in front of which there was a 12 m wide ditch with water. The most important building in the fortress was that of the commandment, being one of the largest buildings known in Dacia (about 1 ha).
In 274 the 5th Macedonian Legion, together with the other Roman troops, withdrew from Dacia. In the ruins of this fortress was discovered the richest category of archaeological material, ceramics, iron and bronze utensils, as well as coins, sculptures, mosaics.